Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
  • C08G65/30—Post-polymerisation treatment, e.g. recovery, purification, drying
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/48—Polyethers
  • C08G18/4866—Polyethers having a low unsaturation value
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2110/00—Foam properties
  • C08G2110/0008—Foam properties flexible

Definitions

• the present invention is concerned with a process for preparing polyether polyols having an oxypropylene content of at least 30% by weight calculated on the total amount of oxyalkylene units in the polyol said polyols having a very low level of unsaturation.
• EP--50181 discloses a process for purifying polyether polyols from alkaline catalysts by neutralizing the polyol with mineral acid, distilling of water and filtration of crystals formed.
• WO-A-90/11990 discloses the reduction of the amount of propenyl impurities by using ion exchange resin.
• diols having a relatively low molecular weight compared to the molecular weight of the major component (i.e. the intended polyol) in the polyol; said relatively low molecular weight diols having a molecular weight which is at least partially overlapping with the molecular weight of the mono-ols.
• these relatively low molecular weight diols which are formed during the oxyalkylating process due to the presence of water in the initiator and/or the alkylene oxide, in principle are unwanted by-products they nevertheless have some value in that their polymer backbone will be fully integrated in the polyurethane polymer network while the mono-ols at least will give pendant chains.
• the mono-ols and low molecular weight diols have a - often a substantially - overlapping molecular weight distribution, surprisingly the mono-ols may be removed preferentially from the polyol. This reduces the amount of waste.
• the present invention is concerned with a process for reducing the level of unsaturation in a polyether polyol having an oxypropylene content of at least 30% by weight calculated on the total amount of oxyalkylene units in the polyol and having a number average equivalent weight of at least 1000 characterised in that the reduction of the level of unsaturation is conducted by subjecting the polyols to ultrafiltration, wherein the polyol having the reduced level of unsaturation did not pass the filter.
• the OH value is determined by end group analysis and quantifies the concentration of hydroxyl groups per unit weight of polyol. It is expressed in the unit of mg KOH/g, the full method is described in the Standard Official Methods of Analysis of ICI Polyurethanes under the reference ICI/OH-1 which is obtainable from ICI Polyurethanes; the amount of oxyethylene units in the polyol in % by weight is determined by C 13 NMR analysis and Y is determined as follows : the Y parameter (unsaturated groups over the total number of end groups) as well as the monool by-product (M), diol by-product (D) and intended polyol (T) molar levels are determined from 13 C NMR analysis.
• the polyols which may be used for reducing the level of unsaturation and the polyols according to the present invention have an average nominal functionality of 2-6, preferably 2-4, a number average equivalent weight of 1000-10000, preferably 1000-8000.
• Suitable polyether polyols which can be employed include those which are prepared by reacting propylene oxide and optionally one or more other alkylene oxides with one or more active hydrogen containing initiator compounds.
• Suitable other alkylene oxides include for example ethylene oxide, tetrahydrofuran, butylene oxides, styrene oxide, epichlorhydrin and epibromhydrin; in particular ethylene oxide.
• Suitable initiator compounds include, for example, water, ethylene glycol, propylene glycol, butanediol, hexanediol, glycerol, trimethylol propane, pentaerythritol, hexanetriol, hydroquinone, resorcinol, catechol, bisphenols, novolac resins, phosphoric acid, sorbitol and sucrose.
• Suitable initiators include, for example, ammonia, ethylenediamine, diaminopropanes, diaminobutanes, diaminopentanes, diaminohexanes, ethanolamine, aminoethylethanolamine, aniline, 2,4-toluenediamine, 2,6-toluenediamine, 2,4'-diamino-diphenylmethane, 4,4,-diaminodiphenylmethane, 1,3-phenylenediamine, 1,4-phenylenediamine, naphtylene-1,5-diamine, 4,4'-di(methylamino)-diphenylmethane, 1-methyl-2-methylamino-4-aminobenzene, 1,3-diethyl-2,4-diaminobenzene, 2,4-diaminomesitylene, 1-methyl-3,5-diethyl-2,4-diamino-benzene, 1-methyl-3,5-
• Most preferred polyols are polyoxypropylene polyols and poly(oxyethylene-oxypropylene) polyols, wherein the oxyethylene may be distributed randomly and/or in blocked form in the chain and/or at the end of the chain, having an average nominal functionality of 2-4, a number average equivalent weight of 1000-5000 and an oxypropylene content of at least 50% by weight calculated on the total amount of oxyalkylene units in the polyols. Therefore these polyols preferably have an OH value of 10 to 60 mg KOH/g.
• average nominal hydroxyl functionality is used herein to indicate the average functionality (number of hydroxyl groups per molecule) of the polyol composition on the assumption that the average functionality of the polyoxyalkylene polyols present therein is identical with the average functionality (number of active hydrogen atoms per molecule) of the initiator(s) used in their preparation.
• the reduction of unsaturation is conducted by ultrafiltration which as such is known in the art, see EP 400554.
• the membranes used in the process according to the present invention have a molecular weight cut off of 1-25K and preferably 1-20K daltons.
• any type of filter having this molecular weight cut off may be used like filters from regenerated cellulose (e.g. Diaflo R membranes from Amicon), polyvinyl chloride, polyacrylonitrile, polycarbonate, polysulfone, polyamide, PVDF (polyvinyl difluoride) and dynel (a vinylchloride - acrylonitrile copolymer).
• the membrane may be in the form of a simple sheet which may have any form (e.g. circular), a spirally wound system, a plate and frame system, a supporting tube system or a hollow fibre system.
• the ultrafiltration may be conducted batch-wise (one or more times) or continuously.
• the polyol which is to be treated can be used as such or is dissolved in a solvent which should be inert to the membrane and the polyol, water not being the sole solvent.
• solvents are methanol and ethanol and mixtures thereof and mixtures of these solvents with water in a 10/90-90/10 weight ratio.
• solvents which dissolve the polyols are for instance acetone, tetrahydrofuran, dichloromethane, butanol and propanol. Further selection of suitable solvents is determined by their inertness towards the membrane system selected.
• solutions containing 1-50% by weight of polyol are employed.
• the solution is brought into contact with the membrane at ambient temperature or, if desired, at elevated temperature provided the ultrafiltration device is able to withstand this temperature and the solution is allowed to pass the membrane by applying a pressure above atmospheric pressure, e.g. 0.2 MPa.
• a pressure above atmospheric pressure e.g. 0.2 MPa.
• the solution may be stirred, if desired.
• Further solvent may be added to the solution during operation e.g. at the same rate at which solvent is passing the membrane. If further purification is desirable filtration may be continued or repeated.
• the solution which did not pass the membrane (the concentrate) is removed from the filtration device and the polyol with the reduced amount of unsaturation is obtained by evaporating the solvent.
• the polyols obtained may be used in the preparation of polyurethanes, in particular flexible foams.
• Another advantage of the ultrafiltration purification is that certain low molecular weight impurities could be removed which impurities could cause an unpleasant smell in flexible foams.
• polyether polyols of the type described above are prepared using certain catalysts, e.g. KOH or CsOH catalysts.
• the active polyol chain may be neutralised in such a way that the metal remains in solution as a salt, e.g. K-adipate.
• the metal salt may be removed as well in a single step together with the compounds containing unsaturation.
• a polyether triol of OH value 28 mg KOH/g, made of PO and EO and containing 15% of ethylene oxide in tip position has been used as the starting product to be purified according to the process described in this invention.
• the unsaturation level was 0.07 meq./g measured by the mercuri acetate method and the parameter Y measured from 13C NMR was 105x10 -3 .
• the monol, diol and triol contents were 27, 17 and 56 mole % respectively.
• the derived molar ratios triol/monool and triol/diol were 2.07 and 3.29 respectively.
• a 2% solution of this product in methanol was prepared.
• the total EO level of the product was 13.5% by weight and the ratio of unsaturated group over the total number of end groups (Y) was 9.10 -3 .
• the monool, diol and triol contents were 2, 19 and 79 mole % respectively.
• the molar ratio of triol : monool was 39.5, showing an improvement by a factor of approximately 19.
• the molar ratio of triol : diol was 4.16, showing a change by a factor of approximately 1.3 only.
• the same polyol as used in example 1 was applied as starting material.
• a 20% solution of this product in methanol/water (50/50 w/w) was prepared. 2 liter of this solution was poured into a feed tank (15°C).
• a diafiltration was conducted as follows.
• the filtration device was a Pellicon tangential flow system from Millipore having a horizontal membrane filter (surface area 0.46 m 2 , membrane : Pellicon cassette from Millipore in regenerated cellulose with MW cut-off of 10.000).
• the solution is passing the membrane tangentially.
• a feed pump was used to feed the solution from the feed tank to the membrane.
• the inlet and outlet pressure of the Pellicon system were 0.55 and 0.21 MPa respectively.
• the permeate containing compounds having unsaturated groups was removed from the lower part of the membrane.
• the concentrate flowed from the upper part of the membrane back to the feed tank.
• a constant liquid level in the feed tank was maintained by feeding 141 of 50/50 w/w water/methanol during the 4 hours the diafiltration was conducted.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyethers (AREA)
• Polyurethanes Or Polyureas (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Polyesters Or Polycarbonates (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)
• Preparation Of Compounds By Using Micro-Organisms (AREA)

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• 1993
  • 1993-06-15 GB GB939312256A patent/GB9312256D0/en active Pending
• 1994
  • 1994-05-13 GB GB9409617A patent/GB9409617D0/en active Pending
  • 1994-05-17 TW TW083104460A patent/TW319783B/zh active
  • 1994-05-24 DE DE69417888T patent/DE69417888T2/de not_active Expired - Fee Related
  • 1994-05-24 ES ES94918363T patent/ES2130427T3/es not_active Expired - Lifetime
  • 1994-05-24 AU AU69714/94A patent/AU676744B2/en not_active Ceased
  • 1994-05-24 EP EP94918363A patent/EP0703936B1/en not_active Expired - Lifetime
  • 1994-05-24 WO PCT/EP1994/001665 patent/WO1994029362A1/en not_active Ceased
  • 1994-05-24 CA CA002162864A patent/CA2162864A1/en not_active Abandoned
  • 1994-05-24 JP JP7501248A patent/JPH08511046A/ja active Pending
  • 1994-05-24 CN CN94192459A patent/CN1044000C/zh not_active Expired - Fee Related
  • 1994-06-13 MY MYPI94001506A patent/MY130045A/en unknown
• 1996
  • 1996-11-06 US US08/744,546 patent/US5767324A/en not_active Expired - Fee Related

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